title: A novel strain of Clostridium botulinum that produces type B and type H botulinum toxins.
abstract: BACKGROUND
  Clostridium botulinum strain IBCA10-7060, isolated from a patient with infant botulism, produced botulinum neurotoxin type B (BoNT/B) and another BoNT that, by use of the standard mouse bioassay, could not be neutralized by any of the Centers for Disease Control and Prevention-provided monovalent polyclonal botulinum antitoxins raised against BoNT types A-G.
  
  
  RESULTS
  The combining of antitoxins to neutralize the toxicity of known bivalent C. botulinum strains Ab, Ba, Af, and Bf also failed to neutralize the second BoNT. Analysis of culture filtrate by double immunodiffusion yielded a single line of immunoprecipitate with anti-A, anti-B, and anti-F botulinum antitoxins but not with anti-E antitoxin. A heptavalent F(ab')2 botulinum antitoxin A-G obtained from the US Army also did not neutralize the second BoNT. An antitoxin raised against IBCA10-7060 toxoid protected mice against BoNT/B (Okra) and against the second BoNT but did not protect mice against BoNT/A (Hall) or BoNT/F (Langeland).
  
  
  CONCLUSIONS
  The second BoNT thus fulfilled classic criteria for being designated BoNT/H. IBCA10-7060 is the first C. botulinum type Bh strain to be identified. BoNT/H is the first new botulinum toxin type to be recognized in >40 years, and its recognition could not have been accomplished without the availability of the mouse bioassay.
authors.affiliation: Infant Botulism Treatment and Prevention Program, California Department of Public Health, Richmond, California.
authors.forename: Jason R
authors.initials: JR
authors.lastname: Barash
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Arnon
mesh_terms: D000818:Animals; D000992:Antitoxins / Q000276:immunology; D001905:Botulinum Toxins / Q000096:biosynthesis* / Q000235:genetics; D001906:Botulism / Q000382:microbiology*; D003014:Clostridium botulinum / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004195:Disease Models, Animal; D006801:Humans; D051379:Mice; D009500:Neutralization Tests; D014481:United States
chemical_list: D000992:Antitoxins; D001905:Botulinum Toxins
keywords: Clostridium botulinum; botulinum antitoxin; botulinum toxin; botulism; mouse bioassay